Guide to Large Garrison Buildings

Dwarven Bunker

This structure stores and maintains the garrison's armaments.

Level 1 Doubles the chance for your quest rewards to get a rare or epic Bonus Upgrade. Allows the collection of armor scraps from the orc clans of Draenor for armor transmogrification use (guard transmog).

Comment: I can't stress enough how much this building needs to be your first Large building on your garrison. For example: On Warlords of Draenor there is a new mechanic in place when you turn in quests and loot special items off rare mobs. Any time you get a quest reward, there's a small chance that reward will be rare or Epic instead of the usual green.

Also: The Level 3 BunkerWar Mill is unlocked by completing Filling the Ranks. Progress on this achievement is account-wide so followers leveled by all characters will count towards the total.